Targeted Correction of the Point Mutations of β-Thalassemia and Targeted Mutagenesis of the Nucleotide Associated with HPFH by RNA/DNA Oligonucleotides: Potential for β-Thalassemia Gene Therapy

An RNA/DNA chimeric oligonucleotide was found to be effective in the targeted correction of point mutations in Escherichia coli, plant, and mammalian genomes. This strategy, named chimeraplasty, has the potential for gene therapy of many genetic diseases caused by point mutations. β-Thalassemia is a very common human genetic disease and in most cases it is caused by point mutations. To test whether the chimeraplasty can be used to correct the point mutations responsible for β-thalassemia, we introduced one mutated β-globin gene, βE, into MEL cells and successfully corrected the point mutation of the βE gene with the highest correction efficiency of 1.9%. Furthermore, a targeted —202 C→G mutation of the Gγ-globin gene, which is associated with the elevated Gγ-globin gene expression in the adult stage, was introduced into HeLa and CMK cells by an RNA/DNA oligonucleotide. These results indicated that the chimeraplasty has potential for human β-thalassemia gene therapy.